Emulsifiable mixtures of mineral oil and esters



tes i tent [EQQ 3 971 544 EMULSEFEABLE IviEX'E URES 9F MINE OIL AND EESTERS Howard N. Rue, Media, Pa, assignor to Sun Oil Comparty, Philaeelphia, Pa, a corporation of New Jersey No Drawing. Filed Aug. 14, 1959, Ser. No. 833,687 8 Qiaims. (Cl. 252-333) Aqueous emulsions containing a minor proportion of mineral oil are commonly employed as rolling oil emulsions for the cold rolling of steel, as well as in other industrial applications. Usual practice is to prepare an emulsifiable mixture of mineral oil and emulsifying agent, e.g. alkali metal or nitrogen base sulfonates or carboxylates, and later add the neat oil, i.e. the emulsifiable mixture, to water to produce the emulsion.

The requirements which emulsions must meet in order to be satisfactory in these uses have become increasingly stringent in recent times. The introduction of new alloys and the increasing demands of the industry for higher production rates and better finish strips have been among the factors involved in this chan e. These new requirements, together with other characteristics which the emulsifiable oils and emulsions must in any event possess, have established a set of criteria which have not been completely met by the compositions made available previously.

The present invention provides emulsifiable compositions and emulsions which surpass the previously available compositions in various of the criteria involved and which are satisfactory in all of the essential characteristics of emulsifiable compositions and emulsions meeting modern requirements. These characteristics include, in addition to those mentioned previously, satisfactorily low viscosity and pour point, good load-carrying ability, freedom from staining and corrosive tendenc, good emulsion stability, the ability to drop out dirt in order to maintain clean emulsion, and the ability to provide clean metal strip upon annealing of the metal afiter the rolling operation.

The emulsifiable oil according to the invention has the following composition in parts by volume:

Mineral lubricating oil 50 to 80 Alkali metal or allranolamine salts of petroleum sulfonic acids to 25 Organic monocarboxylic acid 2 to 5 Alkanolamine 0.5 to 4 Alkanol ester of organic carboxylic acid 5 to 20 The alkanolamine and carboxylic acid can be added if desired as preformed salt of the alkanolamine and carboxylic acid, though this is not essential.

The sulfonic acids which are used to prepare the sulfonates preferably have average molecular weight in the approximate range from 375 to 475, though other acids known to be suitable for preparation of oil-in-water emulsifiers can also be used. Sodium sulfonates are preferred, but potassium or lithium or other alkali metal sulfonates can be used.

The composition contains organic carboxylic acid both in the form of an allcanol ester, and in the form of alkanolamine salts. In each case, the carboxylic acid has 12 to 26 carbon atoms per molecule or an average number of carbon atoms per molecule within that range. The same acid or acid mixture can be used in both cases; however, it is preferred in some cases to use different acids, for example "to use naphthenic acids as the alkanolamine salts and fatty acids as the alkauol esters. Suitable acids which can be employed include, in addition to fatty acids and naphthenic acids, abietic acid and its hydrogenated and dehydrogenated derivatives, and acids produccd by liquid phase partial oxidation of hydrocarbon mixtures such as petroleum lubricating oil. Those carboxylic acids which are known in the art as being suitable for the preparation of alkali metal or nitrogen base salts having oil-in-water emulsifying properties, are generally suitable for use according to the invention.

Suitable alkanols for use in preparation of the esters include methanol, ethanol, isopropanol and higher alkanols, preferably not containing more than 8 carbon atoms per molecule. Still higher alkanols could be used, but there would be little or no advantage to be obtained, and possibly some detriment to desired properties of the composition.

Fatty acid esters of the alkanols are generally preferred because of their good load-cairying properties, but as noted previously esters of other carboxylic acids can be employed.

Pure fatty acids such as palmitic, oleic, and stearic can be employed, or mixtures derived from the known natural glycerides such as lard oil, palm oil, coconut oil, tallow etc.

Petroleum naphthenic acids are preferred for use as the alkanolamine salts in the composition according to the invention, because of the low gelation tendency of alkanolamine naphthenates, but other acids can be used satisfactorily in some cases.

The mineral lubricating oil which is employed preferably has Saybolt Universal viscosity at F. within the approximate range from 50 to 500 seconds. However, those mineral lubricating oils which are known for the preparation of emulsifiable oils for use as emulsions in metal working operations are generally suitable for use according to the invention, and higher viscosities can be employed in some cases. Since relatively low viscosity of the emulsifiable oil is frequently desired, it is usually beneficial to use a relatively low viscosity oil. The pour point of the oil component is also preferably fairly low, in order that the pour point of the emulsifiable mixture with sulfonates and other components also has relatively low pour point, e.g. below 0 F A substantially wax-free oil is therefore preferably used.

The amount of ester employed in the composition according to the invention depends on the extent of the load to which the emulsion will be subjected in the rolling or other metal-working operation, and therefore upon the characteristics of that operation. Where heavy loads must be borne, 15 percent or more of ester may be needed, while in less severe applications, less than 15 percent will be sufficient.

The amount of sulfonates and carboxylates employed depends on the emulsifying characteristics of the oil and ester employed, on the type of water in the emulsion, and on the characteristics of the rolling or other operation. Relatively high sulfonate concentrations, e.g. 1.5 percent or higher, may be needed where hard water is to be used, or where unusually good emulsion stability or a reverse of emulsifying agent is needed during the metalworking operation. In other cases, sulfonate concentrations less than 15 percent may be sufiicient.

Themineral oil content is arrived at by difference, and may for example be 65 percent or higher where relatively large amounts of other materials are needed, and lower than 65 percent in other cases.

The alkanolamine component of the composition according to the invention can be any of the alkanolamines which are known for use in emulsifiable compositions. Examples of suitable materials are ethanolamine, die'tlianolamine, triethanolamine, isopropanolamine, diisopropanolarnine, tr-iisopropanolamine, isobutanolamines, N-aminoethyl ethanolainine, N-phenyl ethanolamine, etc.

The presence of a small amount of water, e.g. 0.5 to 5 weight percent, and usually at least 2 weight percent, in the emulsifiable oil, facilitates the emulsification of the oil upon addition of a large amount of water, and is therefore preferred, though not essential, according to the invention.

It is within the scope of the invention to supply alkali metal cation, if any, and alkanolamine to the composition according to the invention in any suitable manner, and in any amount and ratio that provides an approximately stoichiometric amount for the neutralization of the sulfonic and carboxylic acids. A slight excess, preferably not more than one weight percent, of free carboxylic acid may be provided, or a small excess of alkanolamine, preferably not more than 3 Weight percent based on the emulsifiable composition. Where alkali metal is used, it is not essential that all the sulfonic acid be neutralized with alkali metal, nor that all the carboxylic acid be neutralized with alkanolamine. However, amounts of alkali metal cation which are within the limits of 20 percent less than and 20 percent more than the stoichiometric amount for neutralization of the sulfonic acids, and amounts of alkanolam-ine which are within similar limits based on the amount needed for neutralization of the carboxylic acid, have been found to be particulanly suitable from the standpoint of providing god corrosion inhibiting properties and good load-carrying properties while avoiding undue expense for larger amounts of alkanolamines. It is within the scope of this embodiment to use alkanolamine salts of the sulfonic acids and alkali metal salts of the naphthenic acids, though the use of alkali metal sulfonates is preferred because of the lesser gelation tendency sometimes encountered therewith as compared with alkanolamine sulfonates.

The superior lubricating, load-carrying and corrosioninhibiting properties of the compositions according to the invention are attributable in part to the use of alkanolamine salts in the composition, and to the combination of those salts with the other components.

The emulsificaition of the emulsifia'ole oil according to the invention is accomplished by mixing with water in the conventional manner. Usually, the emulsion will contain 1 to percent of the emulsifiable oil and 90 to 99 percent of added water, but other proportions can be used in some cases. Hard or soft water can be used, and the usual emulsification temperatures, e.g. in the range from 40 F. to 200 F., are generally suitable.

The emulsifiable composition and emulsions according to the invention are useful in a variety of metalworking applications for which oil-in-water emulsions are known to be useful, but they are panticularly well suited for use in the cold rolling of steel.

The following examples illustrate the invention:

Example 1 The following composition is prepared, amounts being given in parts by volume: Mineral lubricating oil (API gravity 22.5; Saybolt Universal viscosities of 105 seconds at 100 F. and

39 seconds at 210 F.) 71.5 Sodium petroleum sulfonate concentrate (66.7%

sulfonates having average molecular weight of 450, 33.3% mineral lubricating oil) 12.0 Petroleum naphthenic acids (average number of carbon atoms about 21) 4.0 Isopropanolamines (mixed mono-, di-, and tri-isopropanolamine) 25 Methyl esters of lard oil fatty acids 10:0

The methyl esters have the following properties: density, 7.36 pounds per gallon; Saybolt Universal viscosity at 100 F., 51 seconds; and pour point, 40 F. The en-- A 5 percent emulsion of this composition in tap Water at 77 F. has pH of about 9.4 and shows no separation of components after standing for about 24 hours. This emulsion does not rust either cast iron plate or cast iron chips in 24 hours at room temperature.

In commercial scale tests, in the cold rolling of carbon and stainless steels on a single stand reversing mill, an aqueous emulsion of the above composition gives highly satisfactory results with respect to production rate, emulsion stability, freedom from staining and corrosion, cleanliness of emulsion after a six-Week period (the usual life of a rolling emulsion being one to six weeks), cleanliness of annealed strip, and other necessary features.

In cleanliness of emulsion, after extended use, the composition according to the invention gives superior results to those obtained with a commercial emulsifiable oil containing no substantial amount of ester.

The composition according to the invention, containing alkanol esters of carboxylic acids, is superior to commercial oils containing glyceride esters such as fats and monoglycerides, with respect to solubility of the esters in mineral oil, and provides neat oil which has lower viscosity and pour point. In rolling performance, the emulsion of the composition according to the invention is equal or superior to such commercial oils in the essential requirements of rolling oil performance. It is superior, for example, in that a cleaner strip is obtained upon annealing following the rolling operation.

The composition according to the invention has superior load-carrying properties, as compared with various commercial oils which lack the combination of components according to the invention. A 3 percent emulsion of the composition of this example in the Falex machine bears increasing loads up to about 3000 lbs. before seizure, whereas one commercial oil containing 3 percent glyceride, 10 percent sodium sulfonates and 1.5% sodium carboxylates bears only about 2300 lbs. before seizure, and another commercial oil containing 20% glyceride and 8% of nonionic emulsifier bears only about 1800 lbs. before seizure.

Example 2 The following composition is prepared:

Mineral lubricating oil 58.7 Sodium petroleum sulfonate concentrate 22.0 Oleic acid 2.2 Isopropanolamines 1.1 Methyl esters of lard oil fatty acids 16.0

All components, with the exception of the oleic acid, are the same as in Example 1.

The composition has API gravity of 19.5, Saybolt Universal viscosity at 100 F. of 198 seconds, pour point of about minus 20 F. By A.S.T.M. sulfonate analysis, the composition contains 14.5 weight percent sodium sulfonates, 2.2 weight percent carboxylic acids as sodium carboxylates, 81 Weight percent oil including esters, and 2 weight percent water. The 5% tap water emulsion is stable and does not rust cast iron plate or cast iron chips. The 3% emulsion bears about 3500 lbs. in the Falex machine, and has performance characteristics in the cold rolling of steel which are somewhat superior, because of the larger amounts of sulfonates and esters, to those of the emulsion of Example 1.

Generally similar results to those obtained in the preceding examples are obtained when using other components and proportions such as those disclosed previously.

The invention claimed is:

1. An emulsifiable composition adapted for the preparation of oil-in-Water emulsions containing 90-99 weight percent water which comprises, in parts by volume: Mineral lubricating oil 50 to Petroleum sulfonates 5 to 25 Organic monocarboxylic acid having 12 to 26 carbon atoms per molecule 2 to 5 Alkanolamine 0.5 to 4 Alkanol ester of organic monocarboxylic acid having 12 to 26 carbon atoms per molecule 5 to said sulfonates being selected from the group consisting of alkali metal petroleum sulfonates and alkanolamine salts of petroleum sulfonic acids, each said monocarboxylic acid being selected from the group consisting of fatty acids, petroleum naphthenic acids, abietic acid, hydrogenated abietic acid, dehydrogenated abietic acid and acids produced by liquid phase partial oxidation of hydrocarbon mixtures, each said alkanolamine having 1 to 3 hydroxyalkyl groups per molecule and 2 to 4 carbon atoms per hydroxyalkyl group, and said alkanol containing 1 to 8 carbon atoms per molecule.

2. A composition according to claim 1 wherein the oil content is to the sulfonate content 5 to 15%, and the ester content 5 to 15%.

3. A composition according to claim 1 wherein the oil content is 50 to 65 the sulfonate content 15 to 25 and the ester content 15 to 30%.

4. An aqueous emulsion composition suitable for the cold rolling of steel which comprises: 1 to 10 weight percent of an emulsifiable composition as defined in claim 1; and to 99 Weight percent of Water.

first named monocarboxylic acid is petroleum naphtheni'c acids.

8. A composition according to claim 1 wherein the water content is in the approximate range from 0.5 to 5 weight percent.

References Cited in the file of this patent UNITED STATES PATENTS 2,079,803 Holtzclaw et al. May 11, 1937 2,145,239 FlaXm-an Ian. 31, 1939 2,179,067 Smith .d Nov. 7, 1939 2,210,140 Colbeth Aug. 6, 1940 2,238,478 Ott Apr. 15, 1941 2,328,727 Langer Sept. 7, 1943 FOREIGN PATENTS 446,314 Great Britain Apr. 28, 1936 

1. AN EMULSIFIABLE COMPOSITION ADAPTED FOR THE PREPARATION OF OIL-IN-WATER EMULSIONS CONTAINING 90-99 WEIGHT PERCENT WATER WHICH COMPRISES, IN PARTS BY VOLUME: 